docs: def send_badge_messages(self, badge_award):
          """
          If the Badge class defines a message, send it to the user who was just
          awarded the badge.
          """
          user_message = getattr(badge_award.badge, "user_message", None)
          if callable(user_message):
              message = user_message(badge_award)
          else:
              message = user_message
          if message is not None:
              badge_award.user.message_set.create(message=message)